In particular, the primary implement can be the main cutting unit of the combine harvester. So, for instance, it can be a grain or a maize cutting unit. In particular, the secondary implement can be a mowing unit, a cutting unit, or a swathing unit.
The secondary implement is arranged further to the rear of the header of the combine harvester than the primary implement. This means that during normal operation in the forward travel of the combine harvester, first the primary implement fulfils its function, and after further movement, the secondary implement fulfils its function. In normal operation, the movement of the secondary implement is arranged such that it moves parallel to the ground. This ensures an even processing of the ground.
In the case that impediments—e.g. deep ground undulations, trenches, rocks, etc.—must be crossed, the whole header, including the two implements, is lifted. However, if the header is one that is used for the so-called “high-cut” operation, there is the problem that, although the primary implement has been lifted up sufficiently high to pass over the impediment, the secondary implement, which is much closer to the ground, is too low for this. Thus, there is the danger of damage to the secondary implement when passing over the impediment.
A similar problem emerges during road transport of the header when it is dismounted from the combine harvester. When the header is separated from the combine harvester and loaded onto a trailer for road transport, then both implements attached to the harvester must be lifted over the wheels of the trailer. In the above described arrangement of displacement in the vertical direction of the two implements, the problem arises that, although the primary implement is arranged above the wheels, the secondary implement will still collide with them.
The header may further comprise a link coupled with the secondary implement. Now, to overcome the problems described above, the new header can comprise a lifting device with a slide element that is formed in such a manner and that is connected with the link so that a translational movement of the slide element causes with a lifting of the secondary implement relative to the primary implement. In this way, the height difference between the lowest point of the primary implement and the secondary implement is compensated in whole or at least in part. The header can be guided and loaded onto a trailer without the danger of a collision. In this way, the construction space available for the protected arrangement of the secondary implement can be optimally used.
The header has at its rear, as seen in the direction of travel, and in its centre an intake duct. The purpose of the intake duct is to take away the crop which have been cut by the primary implement and to feed it to a next processing step. It should be understood that the term “central zone” means the central plane in the longitudinal direction of the combine harvester and the header, perpendicular to the direction of travel. In other words, the central zone means the zone of the axis of symmetry of the header, extending outwardly in both directions. This central zone is to be distinguished from both outer zones on both sides of the combine harvester.
The bottom of the intake duct is already arranged to be very low—i.e. relatively close to the ground. Furthermore, piston-cylinder units are disposed in this area to lift or lower the complete header.
When the secondary implement, after raising the complete header by means of the lifting device, is lifted with respect to the primary implement to position the cutting unit of the primary implement into a protected lifted position, then the problem arises of a possible collision of the central set of rollers with the previously described piston-cylinder units and/or the intake duct.